docs: def standardize(self, axis=1):
          """
          Divide by standard deviation either within or across records.
  
          Parameters
          ----------
          axis : int, optional, default = 0
              Which axis to standardize along, within (1) or across (0) records
          """
          if axis == 1:
              return self.map(lambda x: x / std(x))
          elif axis == 0:
              stdval = self.std().toarray()
              return self.map(lambda x: x / stdval)
          else:
              raise Exception('Axis must be 0 or 1')